On 13 September 2025, the Japan Maritime Self-Defense Force (JMSDF) vessel JS OSUMI (LST-4001) took part in a Multilateral Maritime Cooperative Activity (MCA) in the South China Sea alongside the Philippine Navy and the US Navy.

Japan, the Philippines, and the United States, as maritime partners, reaffirmed their commitment to advancing the vision of a Free and Open Indo-Pacific (FOIP). Through this MCA, the three nations aim to promote regional stability and maritime security in accordance with international law, including the United Nations Convention on the Law of the Sea (UNCLOS).

“The three countries reaffirmed their unwavering partnership in the region and will continue to work in close coordination to uphold lasting peace, prosperity, and security throughout the region,” the Philippine Air Force said in a statement.

The joint maritime exercise highlights the continued collaboration among allies in ensuring a rules-based order in the Indo-Pacific and strengthening their collective maritime capabilities.